


Calculated Risk

by hellhoundsprey



Series: ficlet prompts [17]
Category: Supernatural
Genre: Alien Sam Winchester, Alternate Universe - Science Fiction, Bottom Dean Winchester, Bulge Kink, Impregnation Kink, M/M, Oviposition, Scientist Dean Winchester, Tentacles, Top Sam Winchester, pre-discussed consent
Language: English
Status: Completed
Published: 2020-06-18
Updated: 2020-06-18
Packaged: 2021-03-04 01:46:52
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 598
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24785635
Author URL: https://archiveofourown.org/users/hellhoundsprey/pseuds/hellhoundsprey
Summary: Prompt: !!!!! So happy you’re taking prompts. Congrats on the fic count!!! Could you do something with: wincest, bottom!dean, Sam somehow turned into a tentacle monster, oviposition, tentacles everywhere, and belly bulging? My guilty pleasure from one of my favorite bloggers... imma die.
Relationships: Dean Winchester/Sam Winchester
Series: ficlet prompts [17]
Series URL: https://archiveofourown.org/series/478657
Comments: 3
Kudos: 116





	Calculated Risk

“Fuck…”

“You okay?”

“I’m…”

Dean tips his head back with a groan, with his hands slipping on the railing Sam has been cornering him against. The water ripples around them.

Forgotten, another, “I’m,” but a hand wraps around his neck, flicks at his mouth and pushes inside in time with Sam’s mating tentacle invading him even deeper.

The noise his throat produces feels like it should be more…shocked.

Less fucking _needy_.

“Better than okay? Yeah.” Dean’s hands want to shove at the tentacles wringing around his cock, but he’s too out of it, too focused on gripping the railing for well-needed support. “Yeah, there you go.”

He’s been dripping prior to getting jacked off and the only thing stopping him from coming on the spot is the tiny tentacle stuffing itself down his urethra.

He does attempt to slap at that one but gets his wrist caught; gets the back of his neck bitten and he’d vocalize _some_ sort of protest if it wasn’t for the tentacle face-fucking him.

As is, he groans—frustrated, pinned, writhing in the supernaturally strong grip of species 54 M, or, in short, ‘Sam’.

“Stop whining,” he hears.

Another burst of liquid deep inside of him.

Sam assures him how, “You can take it,” and the tempo picks up, hammers the ribbed seemingly endless mating tentacle into Dean’s ass, his guts, somewhere behind his navel.

Dean protests, weakly, but Sam lifts him higher, bends and holds him like he wants. Dean’s wrists are tied together now in one massive curl of mucosa-covered muscle, at chest-height so he can’t do anything, can’t move—not that he’d particularly want to, but.

They talked about this. Sam and him. Not Dean and Dean’s supervisor, nah, but…if Dean’s doing overtime like a maniac, he can at least indulge a little, right? What could go wrong?

Something alarmingly solid and huge pushes against his already-stretched-thin rim and he surges forward, struggles and yelps before that earns him another bite, meaner this time and he forces himself to hold still, to surrender, but God, this shouldn’t be—

The thrill of relief lasts only for the moment of the thing popping into him and withers quickly with it continuing to travel further.

“See? Told you.” A thumb to Dean’s stretched-out ass, the thick lip of it pulling inside-out on each slow downstroke. “Doing so good for me, Dean.”

Dean would counter something like how Sam’s welcome, if he could.

Whimpers pathetically instead, though, when another announces itself and demands the same hospitality the first one got.

“Only a couple more,” purrs Sam, and Dean shivers head-to-toe. On a molecular level.

A spiritual one, for God’s sake.

The egg—must be an egg, that makes sense, right?—finds its exit through Sam’s mating tentacle and settles neatly inside the warmth of Dean’s guts. Is followed by another gush of liquid—thick and sticky and Dean’s had it in his mouth before and swears he can taste it _now_.

He doesn’t have to look down (not that he could with the grip Sam’s got on him) to know that his stomach is beginning to bulge out with the new weight of Sam’s eggs, the sheer amount of his semen coating them so nicely. Dean’s starting to get light-headed with it.

The stretch on the skin over his stomach increases so rapidly it almost hurts.

Almost.

“So beautiful.”

Sam’s hand feathers over the immense swell of Dean’s stomach. Holds it, all possessive, while he empties another batch of eggs with the others.

Repeats, softly, like an apology, “Only a couple more.”


End file.
